This invention relates to pressure vessels. In one of its aspects, this invention relates to maintaining a constant pressure within a vessel. In another of its aspects, this invention relates particulalry to testing apparatus requiring maintenance of a constant pressure.
In the evaluation of certain geological samples, it is desirable to hold the sample under a constant pressure for a considerable length of time. For such service, a compaction cell is used. Using such an apparatus a pressure of 25 lbs/sq. in., or lower, up to 30,000 lbs/sq. in., or more, can be maintained on a sample for a period of up to 6 months.
A compaction apparatus has a very small liquid pressure chamber which usually contains about a pint of fluid. Considering the size of the container, the length of time the pressure is to be applied, and the very high pressures involved, it is evident that using the more conventional pressure maintainance equipment in this service involves problems which makes the necessary constant monitoring impractical. This invention provides a method and apparatus for maintaining the required pressure on a system such as a compaction cell or other small vessel requiring a constant pressure over an extended period of time.
It is therefore an object of this invention to provide a method and apparatus for maintaining a constant elevated hydraulic pressure in a small vessel.
Other aspects, objects and the various advantages of this invention will become apparent upon reading the specification and the appended claims.